Cavity Guide

March 1, 2018

Cavity Guide

Cavities, or dental caries, result from tooth decay. The process of tooth decay starts with a weakening of the outer enamel layer of a tooth, and can eventually perforate the enamel and infect the softer underlying layer called dentine. It is at this point that the affected tooth requires a filling.

How cavities are assessed

A shallow cavity will not usually be sensitive, and is often diagnosed visually or by X-ray during a dental examination. This type of cavity is simple to repair with basic fillings. As cavities get deeper, teeth may become sensitive or even begin to ache. These deeper cavities tend to be more complicated, and costly, to repair.


A filling is a material used to repair a cavity or hole in a tooth.

Filling materials
Amalgam is the grey/black material once commonly referred to as a filling, but it is now only one of a number of acceptable materials available to restore the form and function of a tooth. Amalgam fillings take a full 24 hours to cure and, due to the colour, will unfortunately not restore the appearance of a tooth.

Composite resin fillings are white fillings which restore the tooth’s natural appearance, along with restoring both form and function. Resin fillings can be matched to the colour of your teeth so that the filling is nearly invisible. White fillings are completely cured when you leave your appointment and the tooth can be used right away.

Gold and porcelain can also be used for indirect fillings.

Direct fillings
Direct fillings are created directly inside the mouth and are generally completed in one appointment. Direct fillings can be made of silver amalgam or white composite resin.

Indirect fillings
An indirect filling may be necessary when a cavity is too large for a direct filling. These fillings are fabricated outside of the patient’s mouth, which allows for strengthening of the filling using processes that cannot be used in the mouth. It commonly takes two appointments to place an indirect filling. Indirect fillings can be made of gold, porcelain or white composite resin. Your dentist will discuss the options available for your filling, and help you to decide on a material that’s best for you.

Preventing cavities

Good dental hygiene at home with proper brushing and flossing is the first step to preventing cavities, and regular check-ups and cleanings with us will ensure that your teeth and gums are clean, and that any cavities that occur are caught and treated early.

Your diet also plays a role in cavity prevention. Certain foods such as calcium and vitamin D are important to the strength of your tooth enamel. Other foods, such as sugary food and drinks or starchy foods such as potato chips and crackers, react with the bacteria on your teeth and produce an acid that destroys tooth enamel. All-day snacking, cough drops or lozenges, and sticky foods can also put you at higher risk of tooth decay and cavities. Read our section on Nutrition and Dental Health for more information about preventing cavities, and refer to our Children’s Dental Health and Infant’s Dental Health sections for specific information on preventing cavities in infants and children.